Untrue, even on flash-based storage full deletion is possible.
Here's an answer I pulled from reddit:
If you are appropriately using TRIM the data will be obliterated when 'garbage collection' occurs -- forensics will not be able to recover deleted data. This is going to be largely dependent on your OS and Hardware, but if you confirm TRIM is working correctly in your setup, shortly after you permanently delete something (not recycle bin or trash) it will be gone for good.
The main takeaway is that people vastly exaggerate how recoverable disks are, making any effort at all will stop 99.9% of hackers trying to recover data.
Here's an answer I pulled from reddit:
If you are appropriately using TRIM the data will be obliterated when 'garbage collection' occurs -- forensics will not be able to recover deleted data. This is going to be largely dependent on your OS and Hardware, but if you confirm TRIM is working correctly in your setup, shortly after you permanently delete something (not recycle bin or trash) it will be gone for good.
The answer is that simple.
Supporting data: http://forensic.belkasoft.com/en/why-ssd-destroy-court-evide... http://digitalforensicsmagazine.com/blogs/?p=271 http://www.mcgoverngreene.com/advoedges/AE_pdfs/2011_pdfs/AE... http://www.forensicswiki.org/wiki/Solid_State_Drive_(SSD)_Fo...
There's also this as a less reliable added measure:
http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml
The main takeaway is that people vastly exaggerate how recoverable disks are, making any effort at all will stop 99.9% of hackers trying to recover data.